Water needs: Once established, water deeply once or twice a month or not at all.

Snapshot: And you thought crocuses bloom only in spring. But this bright yellow crocus pops up out of nowhere in early fall, saving its golden show for September instead of March. Lustrous deep-green foliage emerges soon after the blooms and lasts through the winter. This ultra-easy-care plant thrives in full sun and is extremely drought-tolerant; it will bloom even if you forget to water it. It’s great for rock gardens. You can see specimens in bloom next month in the Arboretum’s Teaching Nursery on the UC Davis campus.